The melting temperature and the structure of fluorine containing polymers

Gal'perin, Ye.L.; Tsvankin, D.Ya.

doi:10.1016/0032-3950(76)90419-6

Cited by 11 publications

(5 citation statements)

References 15 publications

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“…Ethylene−tetrafluoroethylene (ETFE) alternating copolymer with molar content of E/TFE 50/50 mol % is used in the various application fields due to its excellent chemical stability, thermal stability, electric properties, and so on . As reported by several researchers, − this copolymer exhibits the reversible phase transition at around 100 °C between the low-temperature and high-temperature phases, reflecting on the physical properties sensitively. Crystal structure and phase transition behavior are basically important for understanding the characteristic properties of the polymer.…”

Section: Introductionsupporting

confidence: 63%

Crystal Structure Analysis of Ethylene−Tetrafluoroethylene Alternating Copolymer

2011

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INTRODUCTIONEthylene-tetrafluoroethylene (ETFE) alternating copolymer with molar content of E/TFE 50/50 mol % is used in the various application fields due to its excellent chemical stability, thermal stability, electric properties, and so on. 1 As reported by several researchers, 2-10 this copolymer exhibits the reversible phase transition at around 100°C between the low-temperature and hightemperature phases, reflecting on the physical properties sensitively. Crystal structure and phase transition behavior are basically important for understanding the characteristic properties of the polymer. The whole scheme of the phase transition behavior of this ETFE copolymer is clarified relatively well. But, we have still one serious and not-yet-perfectly solved problem, which is needed to solve correctly for understanding the structural transition behavior in a concrete manner. The problem is to analyze the accurate crystal structure of this copolymer. The molecular chain conformation and the crystal structure of both the low-and high-temperature phases must be clarified with enough accuracy, in particular, the structure of the low-temperature phase as a starting point of discussion.So far, several researchers reported the crystal structure of the lowtemperature phase, but the correct answer is still ambiguous. 10-12 For example, Wilson and Starkweather proposed the monoclinic structure with space group C2/m-C 2h 3 and a = 9.6 Å, b = 9.2 Å, c (fiber axis) = 5.0 Å and γ = 96°, and also the structure of orthorhombic cell with space group Cmca-D 2h 18 . 11 But they did not determine the structure through the quantitative comparison of X-ray diffraction intensities between the observed and calculated values. Tanigami et al. proposed the orthorhombic unit cell of a = 8.57 Å, b = 11.20 Å, and c (fiber axis) = 5.04 Å, in which four planar-zigzag chains were packed in a herringbone mode. 12 The setting angle of planar-zigzag chains was determined by comparing the observed and calculated intensity ratio of the two innermost equatorial X-ray reflections (120 and 200). But, their model does not give a good agreement between the observed and calculated intensities of many other reflections, as will be checked in a later section of the present paper. Besides, judging from the source, their sample is speculated to contain small amount of the third monomer content and it is not a purely two-component ETFE copolymer. Existence of the third component might affect the unit cell parameters as well as the X-ray diffraction pattern itself. 13 Phongtamrug et al. determined the unit cell parameters for a series of ETFE copolymers with various E/TFE contents. 10 Since the innermost reflection was found to be an overlap of two reflections of slightly different lattice spacings, their proposal of monoclinic unit cell might be reasonable. But they did not give any plausible crystal structure model in their paper.In this way, the crystal structure of ETFE alternating copolymer has not yet been established enough satisfactorily. In the present pape...

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Section: Introductionsupporting

confidence: 63%

Crystal Structure Analysis of Ethylene−Tetrafluoroethylene Alternating Copolymer

2011

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“…The heats of fusion were calculated using a linear baseline and constant integration limits of 125±180 ³C, 210±295 ³C, and 230±285 ³C, in the case of the PVDF, FEP, and ETFE ®lm samples, respectively. The heats of fusion of 100% crystalline PVDF, FEP, and ETFE have been reported to be 22,23 104.6, 87.9, and 113.4 J g 21 .…”

Section: Film Characterizationmentioning

confidence: 99%

Grafting of pre-irradiated poly(ethylene-alt-tetrafluoroethylene) films with styrene: influence of base polymer film properties and processing parameters

et al. 2000

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The radiation grafting method is of interest for the preparation of ion-exchange membranes for electrochemical and other applications. Typically styrene is used in this method because the grafted polystyrene can be readily modi®ed to introduce a variety of functionalities. The grafting of poly(ethylene-alt-tetra¯uoroethylene), or ETFE, ®lms with styrene by the pre-irradiation method has been investigated and compared to that of poly(tetra¯uorethylene-co-hexa¯uoropropylene), or FEP, and poly(vinylidene ¯uoride), or PVDF. The in¯uence of base polymer ®lm properties such as ®lm thickness, extent of orientation, and molar mass on the grafting behavior of ETFE ®lms is reported. Film orientation was found to often have a dominant in¯uence either directly, as in the case of monoaxially oriented ®lms, or indirectly, as a result of the ®lm extrusion process. In addition, the effects of the irradiation type and atmosphere and grafting temperature on the grafting behavior of one ETFE ®lm type were examined in more detail.

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“…has not been confirmed. The glassy temperature of the amorphous fraction is similar to that reported previously 29…”

Section: Resultsmentioning

confidence: 99%

Emulsion copolymerization of tetrafluoroethylene with ω‐chlorotetrafluoroethyltrifluorovinyl ether and the synthesized copolymer properties

Allayarov

Ilyin²,

Ol’khov

et al. 2011

J of Applied Polymer Sci

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Emulsion copolymerization of ω‐chlorotetrafluoroethyltrifluorovinyl ether (Cl(CF2)2OCF = CF2 (FVE)) with tetrafluoroethylene (CF2 = CF2 (TFE)) was investigated at various monomer ratios. The copolymerization rate is below the rate of TFE homopolymerization and the copolymerization kinetics depends on the FVE content in the reaction medium. The copolymer composition is very similar if the FVE content in monomer mixture is ≤2.5 mol %. However, the percent amount of FVE in the copolymer, the copolymerization rate, and molecular mass of synthesized copolymers decrease noticeably with increase in the FVE content in the monomer mixture. The constants of copolymerization are r1= 2.8 (TFE) and r2 = 0.03 (FVE). The copolymer is a statistical polymer consisting of TFE blocks and individual FVE molecules between the blocks. The average molecular mass of copolymers is significantly less than that of the TFE homopolymer (PTFE) synthesized at the same conditions. The morphologies of PTFE and copolymer powders were investigated by thermomechanical analysis and are not similar. The copolymer has a completely amorphous diblock morphology depending on the FVE content. The introduction of FVE molecules into the copolymer macromolecules is accompanied by reduction of the crystalline portion of copolymer. If the FVE content in copolymer is ≥3.5 mol %, the copolymer macromolecules completely lose the ability to form crystalline portions as a result of their amorphicity. The introduction of up to 2.4 mol % FVE into the copolymer macromolecules yields a highly thermostable and meltable copolymer which can be processed by using the industrial processes used widely for thermoplastics. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

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The melting temperature and the structure of fluorine containing polymers

Cited by 11 publications

References 15 publications

Crystal Structure Analysis of Ethylene−Tetrafluoroethylene Alternating Copolymer

Crystal Structure Analysis of Ethylene−Tetrafluoroethylene Alternating Copolymer

Grafting of pre-irradiated poly(ethylene-alt-tetrafluoroethylene) films with styrene: influence of base polymer film properties and processing parameters

Emulsion copolymerization of tetrafluoroethylene with ω‐chlorotetrafluoroethyltrifluorovinyl ether and the synthesized copolymer properties

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